The present invention relates to a switch with programmable delay, in particular, an integrated circuit for use as a secondary side post regulator PWM (pulse width modulator) controller.
There are a number of post regulator methods for power control in a multiple output power regulator. The most popular in the mid to high power range are magnetic amplifiers. The magnetic amplifiers permit circuitry with low component count and simple thermal management. At low and medium frequencies, the magnetic amplifiers are cost competitive. However, at high frequencies, the suitable magnetic amplifiers become much more expensive. Problems are also often encountered with magnetic amplifiers in terms of overcurrent or turn off protection.
A leading edge modulated synchronous switch post regulator is the semiconductor equivalent of the magnetic amplifier post regulator. The need for a synchronous switch post regulator integrated circuit has existed for quite some time. Cliff Jamerson and Tony Long in their article "Design Techniques for Synchronous-Switch Post Regulators", HFPC May 1993 Proceedings, specifically urged the development of such an integrated circuit to reduce the parts count associated with this regulation technique. One object of the present invention is to fill this need.